The following art defines the present state of this field:
Great Britain Patent Application Publication No. GB2413824 to Bysveen, et al. describes a diesel-cycle internal combustion engine which operates using a liquified hydrocarbon gas fuel containing an ignition improver, eg a cetane improver. The gas may be supplied to the combustion chambers using a common rail fuel supply system. The fuel and method of operating the diesel-cycle engine can be used in a range of applications such as, for example, road or marine vehicles or in static applications such as electrical generators. The fuel and the ignition improver may both be supplied to the engine in liquid form either pre-mixed in bulk (FIG. 1); kept in separate tanks 202, 204, pressurised by separate pumps 207, 208 and mixed in the injector 206; or mixed before reaching a common rail (301, FIG. 3A) or within a common rail (305, FIG. 3B). Alternatively, eg with methane or natural gas, the fuel may be pressurised rather than liquefied and the ignition improver is suspended as a mist in the gas. The fuel may be eg methane, ethane, propane, butane or natural gas. The ignition improver may be diesel fuel, any mixture of alkanes and alkenes, a mono-ether, a di-ether, DME (diethyl ether), GTL (Gas-to-Liquid), alkyl and/or aryl nitrates.
U.S. Pat. No. 7,040,281 to Crawford, et al. describes a method of operating a gaseous-fueled internal combustion engine comprises selecting one of at least two predetermined operating modes as a function of engine load and engine speed. A first operating mode is selected when said engine is commanded to operate within a first region corresponding to a low load and low speed range, and a second operating mode is selected when said engine is commanded to operate within a second region distinct from said first region and corresponding to at least one of a greater load and a greater speed range compared to said first region. In the first operating mode, the gaseous fuel is introduced in a single injection event with the injection valve commanded to open with a constant amplitude A1. In the second operating mode, the gaseous fuel is introduced in a single injection event and the injection valve is commanded to begin with a constant amplitude A2 for a predetermined time and then to open to an amplitude A3, wherein amplitude A3 is greater than amplitude A2.
U.S. Pat. No. 7,019,626 to Funk describes systems, methods and apparatus' of converting an engine into a multi-fuel engine are provided. One embodiment reduces particulate emissions and reduces the amount of combusted gasoline or diesel fuel by replacing some of the fuel with a second fuel, such as natural gas, propane, or hydrogen. One feature of the present invention includes a control unit for metering the second fuel. Another feature of the present invention includes an indicator that indicates how much second fuel is being combusted relative to the diesel or gasoline. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.
Japanese Patent Application Publication No. EP1211407 to Watanabe, et al. describes injectors 2 are connected to a common rail 4 via respective dispensing conduits 3. A mixture of a liquid fuel fed from a liquid fuel tank 2 and an additional fluid fed from an additional fluid tank 9 is formed, and is fed to the common rail 4. The additional fluid contained in the mixture is turned to its supercritical state, and the mixture is injected from the injectors 2 to the engine. The inlets of the dispensing conduits 3 are positioned, with respect to the common rail 4, to open out into a liquid fuel layer which will be formed in the common rail 4 when a separation of the mixture occurs.
German Patent Application Publication No. DE19609799 to Danckert, et al. describes an engine can be fed selectively with a first fuel or with a second fuel in the form of clean fuel or an emulsion of fuel and a further material insoluble in relation to the fuel. The fuel is fed in a circuit through the common pre-accumulator (6). The fuel injection equipments (1) have a through passage for the fuel fed from the common pre-accumulator. The part of the fuel not injected from the injection nozzles into the engine is fed back via a return flow conduit (8) to the common pre-accumulator.
U.S. Pat. No. 5,125,367 to Ulrich, et al. describes a method and apparatus for producing a water-in-fuel-emulsion and emulsifier-free water-in-fuel-emulsion. The apparatus for generating a fuel water emulsion for the operation of an injection pump, particularly that of a diesel motor, comprising a rotationally symmetric vortex chamber (1) with a tangential inlet and a tapering axial outlet. In order to generate a fine homogeneous emulsion in colloidal state, having a size of the suspended water droplets of 1000 nm or less, the axial end portion of the vortex chamber (1) facing away from the outlet is surrounded by a ring channel (7) running coaxially to the vortex chamber (1), the ring channel (7) being connected to the vortex chamber (1) via inlet slots (9) which are tangentially aligned to it and in which a fuel inlet channel (8) tangentially ends. An electromagnetically controlled water injection nozzle (10) leads into the end portion of the vortex chamber (1) at the inlet side thereof. The outlet (2) of the vortex chamber (1) opens via an enlargement (3) into a suction chamber (4) of a radial wheel (5) which is arranged in a pump chamber (12) having an outlet channel (13) in the area of the circumference of the radial wheel (5) to which a forward conduit leading to the injection pump and a recirculation conduit leading to an emulsion inlet channel (15) are connectable which also ends tangentially into the ring channel (7). An intake channel (16), to which a return conduit coming from the injection pump is connectable, leads into the suction chamber (4) of the radial wheel (5).
U.S. Pat. No. 6,866,756 to Klein describes an electrolyzer for electrolyzing water into a gaseous mixture comprising hydrogen gas and oxygen gas. The electrolyzer is adapted to deliver this gaseous mixture to the fuel system of an internal combustion engine. The electrolyzer of the present invention comprises one or more supplemental electrode at least partially immersed in an aqueous electrolyte solution interposed between two principle electrodes. The gaseous mixture is generated by applying an electrical potential between the two principal electrodes. The electrolyzer farther includes a gas reservoir region for collecting the generated gaseous mixture. The present invention further discloses a method of utilizing the electrolyzer in conjunction with the fuel system of an internal combustion engine to improve the efficiency of said internal combustion engine.
U.S. patent application Publication Ser. No. 10/277,841 to Klein describes an arrangement and method is disclosed for improving the fuel economy of an internal combustion engine of the type having a carburetor for mixing a fuel with air, in which the air is saturated with a mixture of ether, alcohol and water.
U.S. Pat. No. 4,412,512 to Cotten describes a fuel supply system is disclosed in which oil and water are mixed and delivered under pressure to a nozzle or other atomizing means at which combustion is to occur. The mixture of oil and water is delivered to the atomizing means along conduit means and those conduit means include means to produce agitation of the oil and water so that an intimate mixture of oil and water is delivered to the atomizing means. Complete emulsification occurs at the atomizing means to promote combustion.
More generally, in the prior art, typically a single fuel is held in a tank and fed into the engine through a carburetor or injection system. In a carburetor system liquid fuel is mixed with the air in the carburetor, and the fuel-air mixture is admitted to the combustion chambers through an intake manifold and compressed in the combustion chamber. In an injector system the air is fed into the combustion chambers and the fuel or fuels injected directly into the combustion chamber and mixed with the compressed air. Various embodiments have been run on gasoline, diesel, kerosene, propane, hydrogen, natural gas, generated methane, or other flammable substances. In some embodiments a gaseous enhancement, such as hydrogen, water vapor or nitrous oxide is added to the air inflow stream to increase the power extracted from the liquid fuel. Some engines are modified to run entirely on a gaseous fuel instead of a liquid fuel.